Autologous bone marrow transplantation has been employed to maintain a state of remission in patients with various malignancies, including leukemia. In this procedure, bone marrow of a patient having a malignancy is removed during remission and stored for readministration after the patient relapses into the active presence of the cancer (Gale, R. P. et al., Seminars in Hematology (1987) 24:40-54). As autologous marrow is used, it is not necessary to provide HLA-matched donors (which limits allogenic bone marrow transplants to 6% of the adults with acute myelogenous leukemia (AML)); however, a significant drawback for autologous marrow is that malignant cells may remain in the putatively remitted marrow. There have been a number of attempts to purge remission marrow of residual malignant cells, but these attempts have been less than successful (Champlin R., et al., Seminars in Hematology (1987) 24:55-67; Champlin, R. E., et al., Seminars in Hematology (1988) 25: 74-80; Malik, Z., et al., Brit J Cancer (1987) 56:589-595). The Malik paper describes the destruction of leukemic cells by photoactivation of endogenous porphyrins. In addition, certain amphipatic dyes have been reported to photosensitive leukemic cells to a greater extent in comparison to normal mononuclear cells (Sieber, F., et al., Blood (1986) 68:32-36; Sieber, F., et al., Photochem Photobiol (1987) 46:71-76; Singer, C. R. J., et al., Brit J Hematol (1988) 68:417-422; Tulpaz, M., et al., Seminars in Hematology (1988) 25:62-73).
Compounds useful in the technique of the present invention are described in copending U.S. Ser. No. 07/414,201 filed Sept. 28, 1989 and incorporated herein by reference. These compounds are hydrobenzo derivatives of hematoporphyrin which absorb longer wavelength light, in the range of approximately 670-780 nm, than does hematoporphyrin or alternative medically useful derivative forms. These green porphyrin compounds also exhibit a fluorescence excitation peak at shorter wavelengths which can be used for fluorescence emission in diagnosis. Photoactivation of compounds of this type for the destruction of solid tumors and of infectious organisms is also described.